Code Civ. Proc., § 1710.40

(a) A judgment entered pursuant to this chapter may be vacated on any ground which would be a defense to an action in this state on the sister state judgment, including the ground that the amount of interest accrued on the sister state judgment and included in the judgment entered pursuant to this chapter is incorrect.

(b) Not later than 30 days after service of notice of entry of judgment pursuant to Section 1710.30, proof of which has been made in the manner provided by Article 5 (commencing with Section 417.10) of Chapter 4 of Title 5 of Part 2, the judgment debtor, on written notice to the judgment creditor, may make a motion to vacate the judgment under this section.

(c) Upon the hearing of the motion to vacate the judgment under this section, the judgment may be vacated upon any ground provided in subdivision (a) and another and different judgment entered, including, but not limited to, another and different judgment for the judgment creditor if the decision of the court is that the judgment creditor is entitled to such different judgment. The decision of the court on the motion to vacate the judgment shall be given and filed with the clerk of court in the manner provided in Sections 632, 634, and 635, except that the court is not required to make any written findings and conclusions if the amount of the judgment as entered under Section 1710.25 does not exceed one thousand dollars ($1,000).